Collaborative Research: Comprehensive Analysis of Seismic Processes in a Deep South African Mine

合作研究：南非深部矿井地震过程的综合分析

• 批准号: 0944161
• 负责人: Margaret Boettcher
• 金额: $ 25.6万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944161&HistoricalAwards=false
• 关键词: Collaborative; Research; Comprehensive; Analysis; Seismic

Many fundamental questions in earthquake physics remain unresolved, largely because ofdifficulties in obtaining high-quality, near-source recordings of small earthquakes andderiving reliable source parameters. The overarching goal of this project is to provide animproved understanding of earthquake source processes for a wide magnitude range(approximately -4 to 4). We are performing detailed seismological investigations ofsource properties that characterize several distinct classes of seismic events (earthquakes,rockbursts, and blasts) in a 3.6 km deep South African mine. We will also conduct a shortfield campaign to record seismic events at the extremes of the magnitude range and inclose proximity to fault structures. Full source tensor inversions, second momentanalysis, and spectral methods will be used to determine comprehensive sets of sourceproperties including scalar potencies/moments, focal mechanisms, corner frequencies,strain/stress drops, radiated energies, rupture velocities, and source time functions.Special effort will be devoted to detecting isotropic components of faulting. Theoreticalcalculations of expected radiation from different event types will help in theinterpretation of results.Applying the above analysis to the small-magnitude, near source seismic data will allowus to obtain constraints on many aspects of earthquake physics including nucleationprocesses, the prevalence of isotropic components of seismic radiation, changes in thephysics of rupture with event magnitude or with proximity to geologic and miningstructures, and source parameter differences between earthquakes, explosions, and otherseismic sources. The high-resolution results on seismic source properties and scalingrelations will significantly impact the earthquake physics and rock mechanicscommunities by helping to resolve long-term controversies on earthquake nucleation andrupture processes, scaling of laboratory results to natural faults, and earthquake energybudgets, among others. In addition, the findings on spatially dependent seismic propertieswill be useful for decision-making concerning when and where to suspend miningactivities to enhance underground safety

地震物理学中的许多基本问题仍然没有解决，这主要是因为难以获得高质量的近源小地震记录和导出可靠的震源参数。该项目的首要目标是提供一个更好的了解震源过程的一个广泛的震级范围（约-4至4）。我们正在南非一个3.6公里深的矿井中进行详细的震源特性地震学调查，这些特性描述了几种不同类型的地震事件（地震、岩爆和爆炸）。我们还将进行一次短场活动，记录震级范围极端的地震事件，并靠近断层结构。全震源张量反演、二阶矩分析和谱方法将用于确定震源性质的综合集合，包括标量势/矩、震源机制、角频率、应变/应力降、辐射能量、破裂速度和震源时间函数。对不同事件类型的预期辐射的理论计算将有助于对结果的解释。将上述分析应用于小震级近源地震数据将使我们能够获得对地震物理学许多方面的约束，包括成核过程、地震辐射各向同性分量的普遍性、破裂物理学随事件震级或地质和采矿结构的接近程度的变化、以及地震、爆炸和其他震源之间的震源参数差异。震源特性和标度关系的高分辨率结果将显著影响地震物理学和岩石力学社区，有助于解决长期争议的地震成核和破裂过程，自然断层的实验室结果的标度，以及地震能量预算等。此外，空间相关地震特性的研究结果将有助于决策何时何地暂停采矿活动，以提高地下安全